Scientists have deliberately turned male mouse embryos into females for the first time.

A team based in Japan used a CRISPR-based approach to remove the Y chromosome from male cells and create female clones of male mice.

“ No one has done this before ” says Monika Ward, a reproductive biologist at the University of Hawaii, who was not involved in the research.

The sex reversal technique could be used to help rescue endangered species, say the researchers behind the work.

The feat could change the way scientists think about reproduction, says Takashi Ishiuchi, a reproductive biologist at the University of Yamanashi, who co-led the work.

The findings were published in a preprint paper shared on bioRxiv earlier this month, which has not yet been through the peer-review process.

“ There’s a fixed concept in our scientific field that we need both females and males for reproduction ” says Ishiuchi.

“ I think we could change this concept. ”

He and his colleague Shogo Matoba of the Riken BioResource Research Center in Ibaraki also hope their technique could help rescue endangered species, particularly in cases where only a few individuals remain.

“ It’s exciting to see ” says Ben Novak, lead scientist at the wildlife conservation organization Revive & Restore, who was not involved in the work.

“ I am confident there will be plenty of applications, particularly for conservation purposes. ”

In 2002, a new plastic softener called DINCH went on sale as the answer to a growing health scare. Phthalates, the chemicals that make plastic soft and bendy, had been linked to premature birth and fertility problems, and manufacturers wanted something safer. Now researchers across the United States have checked the urine of thousands of pregnant women for traces of the replacement. Then they looked at the babies.

Most parents of teenagers have heard the warning: too many hours on screens, and depression and anxiety follow. Studies keep finding the link, but they all share one weakness. Kids who game or scroll for hours may already differ from other kids in their genes and their homes. Researchers at the Karolinska Institutet found a way around that problem: twins. They followed 21,797 Swedish twins from age 9 into their twenties.

Schools and colleges around the world are banning phones in class, with little hard evidence on whether it works. So researchers from the University of Pennsylvania, Jawaharlal Nehru University and the University of Copenhagen ran a real experiment. Across 10 colleges in India, 2,305 courses were randomly assigned either to collect phones at the start of every lecture or to carry on as usual. Then they compared the grades of 16,683 students.

Oxford researchers used trapped ions to simulate the Aharonov-Bohm effect, where a particle’s quantum phase shifts just from circling a region of magnetic flux without ever entering it. With no flux, their simulated particle tunneled freely between two locations. Add the flux, and its two possible paths canceled each other out, leaving it stuck in place.

The twist is that the magnetic flux was encoded in a gauge field that evolved alongside the particle instead of sitting fixed in the background. The team says this opens a route to simulating fundamental interactions that conventional computers struggle to model.

A 2016 study by researchers at Yale University published in Social Science & Medicine investigated the relationship between reading and longevity. The study used data from the Health and Retirement Study , a representative sample of Americans who were surveyed repeatedly between 1998 and 2010. Of the 3,635 Americans surveyed, 50 years old and above, those who engaged in regular reading activities had lower mortality risks than those who did not.

The researchers controlled for age, gender, race, education, wealth, marital status, employment status, self-reported health status, eyesight, depression, and chronic disease. When controlling for all these factors, compared to non-readers, book readers had a 20% lower risk of mortality. Additionally, there was a dose-response association, whereby the higher the number of hours read per week, the lower the risk of dying. Specifically, individuals who read for up to 3.5 hours per week had a 17% lower risk of mortality, while those who read more than 3.5 hours per week had a 23% lower risk.

Compared to newspaper and magazine readers, book readers had the highest risk reduction for all levels of reading frequency. The cognitive stimulation theory may explain the observed correlation between book reading and survival. Controlling for covariates, book reading had a significant association with survival. In the unadjusted model, book readers had an 80% survival chance, 23 months longer than the non-reader group. On average, the survival time for readers was 23 months, and the hazard ratio for all-cause mortality was 0.80 among book readers compared to non-readers.

The study establishes a correlation between book reading and increased survival but does not indicate a causal relationship. Further, the analysis was based on a single measure of the exposure variable. Because the study was observational and relied on self-reported data, residual confounding factors could account for the observed association. Finally, although the results were consistent across various models, the study’s findings only apply to older Americans.

Married people tend to live longer, and for decades studies have hinted that men get more out of marriage than women do. Researchers at Chapman University and UCLA went looking for that gap in DNA itself. They took blood samples from 762 American adults, most of them in midlife, and ran them through three epigenetic clocks, tools that estimate how fast the body is aging from chemical marks on the genome. One group stood out.

I always felt there was a benefit to smoking the whole flower compared to the isolates of edibles and vapes

In 2004 and 2005, more than 300,000 South Koreans aged 40 and over went in for a routine national health check. Like most check-ups anywhere, it included a standard blood count, the kind of test that usually gets a quick glance and a "your numbers look fine." Researchers at Dong-A University in Busan then followed those people through national insurance records for up to 15 years to see who developed dementia. One familiar number on that old lab sheet turned out to matter.

Most of us spend our adult lives hearing that extra weight shortens life. For people who already have dementia, a handful of studies have hinted at the opposite, and many researchers have suspected a statistical trick. A team from Columbia University and New York University went back to 24 years of data on older Americans and picked out 4,523 people who developed dementia along the way. Then they tested every explanation for the paradox they could think of.

Millions of people reach for cannabis at night because it seems to help them drift off. Researchers at Northwestern University had an unusual way to test that belief: a group of American adults whose cannabis use had been tracked since they were young adults in the mid-1980s. Now around 60, the participants wore a sleep monitor on the wrist for a week and filled out a sleep questionnaire. The two measurements did not tell the same story.

In 2004, researchers in New York invited hundreds of mothers and their 3-year-olds into a lab to read books and build with blocks while a camera rolled. Coders scored every session for warmth, encouragement and support, and for harshness and intrusiveness. Then the team kept coming back. Over the next 15 years they recorded the brain activity of 465 of those children at ages 9, 12, 15 and 18, focusing on one signal that earlier research has tied to depression. The question was whether a few lab games at age 3 could say anything about how positive parenting shows up in a teenager’s brain.